Mortality trends and influencing factors of mental disorders among urban and rural residents in China between 2009 and 2021: a longitudinal study with projections to 2030

Introduction Mental disorders pose a major public health challenge in China, with marked urban–rural disparities in resources and outcomes. However, long-term mortality trends, their influencing factors, and future projections across urban and rural areas remain underexplored. This study aimed to analyze these mortality trends, identify relevant factors, and project mortality to 2030 using national data from 2009 to 2021. Methods Data were extracted from the China Health Statistical Yearbook , the China Health and Family Planning Statistical Yearbook , the China Health Statistics Yearbook and the China Statistical Yearbook covering the years 2009–2021. Joinpoint regression was used to analyze temporal trends. A two-way fixed effects panel regression model examined associated factors, with additional sensitivity analyses including Oster’s boundary analysis and the exclusion of dementia-related deaths. GM (1,1), ARIMA, and Lasso models were compared for forecasting, and optimistic and pessimistic scenarios were constructed to reflect uncertainty in projections to 2030. Results From 2009 to 2021, urban crude mortality rates (CMR) remained stable, whereas rural CMR increased significantly (AAPC = 1.21%, p  = 0.02), with a sharp rise during 2019–2021 (APC = 13.23%, p  p  β  = 0.650, p   Conclusion This study reveals significant urban–rural disparities in mental disorder mortality, with rural areas experiencing a marked recent increase. Males, the oldest old, and young adults are particularly vulnerable. Population aging showed the strongest association with mortality, and this association persisted after controlling for additional confounders. Scenario projections indicated continued divergence between urban and rural trends. These findings underscore the need for life-course prevention strategies and differentiated resource allocation between urban and rural areas.